summarize two different point of view about the powerful fly in Pterosaurs

The reading asserts that Pterosaurs, an extinct group of reptiles that could fly, could not fly by moving their wings, and the only way they flew in the sky was gliding; nevertheless, the professor disagrees with this argument and mentions that recent researches have proved that Pterosaurs were able to move their wings and fly strongly. To begin with, the author states that Pterosaurs were cold-blooded animals just like modern reptiles, and they could not provide enough energy for a powerful fly. The lecturer challenges this claim and asserts that recently discovered fossils show that these animals had hair and fur on their body. Moreover, she adds that like typical warm-blooded animals, they used this fur to keep their body temperature high in spite of cold environment. Therefore, she believes these animals were not cold-blooded and could produce enough energy for a potent fligh. Secondly, the passage claims that Pterosaurs were too heavy to move their wings swift and keep themseleves up. The listening section, however, refutes this argument and expresses that these animals had a physical feature, allowing them to fly by moving their wings. Additionally, she say that the structure was light and the animal's bones were hollow instead of firm. Thus, this gave the Pterosaurs a light weight in spite of their body size which permitted them to fly powerful. According to the text, in contrast of birds that have strong back leg muscles, the back muscles of Pterosaurs were too weak to help them take off from land. The lecturer opposes this claim, explaining that birds take off with two legs, so they use two limbs to jump and fly. However, Pterosaurs used four legs to walk and run fast and push on the ground. Furthermore, she says that four limbs power were strong enough to let them run swiftly, jump and take off from the land.